Fixed an error where I would attempt to access a non-existent index
Fixed case D6... I think.
- Made highestNonZeroIndex a public method of UInt32Vector to reduce redundancy.
- Cleaned up a lot of the code in MPUInteger.
Note: division is still broken, but some issues have been resolved. In particular the remainder is being set wrong...
Working long division implementation -- or so it seems, still requires *extensive* testing, especially with coverage tests on D6.
Cleaned up the code a bit. Division works. Modulus is broken.